1 files changed, 26 insertions, 10 deletions

diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
index 3f2bff0d3aa2..1cd2b99ab256 100644
--- a/drivers/s390/scsi/zfcp_unit.c
+++ b/drivers/s390/scsi/zfcp_unit.c
@@ -104,7 +104,7 @@ static void zfcp_unit_release(struct device *dev)
 {
         struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
 
-        put_device(&unit->port->dev);
+        atomic_dec(&unit->port->units);
         kfree(unit);
 }
 
@@ -119,16 +119,27 @@ static void zfcp_unit_release(struct device *dev)
 int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 {
         struct zfcp_unit *unit;
+        int retval = 0;
+
+        mutex_lock(&zfcp_sysfs_port_units_mutex);
+        if (atomic_read(&port->units) == -1) {
+                /* port is already gone */
+                retval = -ENODEV;
+                goto out;
+        }
 
         unit = zfcp_unit_find(port, fcp_lun);
         if (unit) {
                 put_device(&unit->dev);
-                return -EEXIST;
+                retval = -EEXIST;
+                goto out;
         }
 
         unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
-        if (!unit)
-                return -ENOMEM;
+        if (!unit) {
+                retval = -ENOMEM;
+                goto out;
+        }
 
         unit->port = port;
         unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
         if (dev_set_name(&unit->dev, "0x%016llx",
                          (unsigned long long) fcp_lun)) {
                 kfree(unit);
-                return -ENOMEM;
+                retval = -ENOMEM;
+                goto out;
         }
 
-        get_device(&port->dev);
-
         if (device_register(&unit->dev)) {
                 put_device(&unit->dev);
-                return -ENOMEM;
+                retval = -ENOMEM;
+                goto out;
         }
 
         if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
                 device_unregister(&unit->dev);
-                return -EINVAL;
+                retval = -EINVAL;
+                goto out;
         }
 
+        atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
+
         write_lock_irq(&port->unit_list_lock);
         list_add_tail(&unit->list, &port->unit_list);
         write_unlock_irq(&port->unit_list_lock);
 
         zfcp_unit_scsi_scan(unit);
 
-        return 0;
+out:
+        mutex_unlock(&zfcp_sysfs_port_units_mutex);
+        return retval;
 }
 
 /**